1. FIELD OF THE INVENTION
This invention relates to the deployment of a side impact system in automobiles, and, more particularly, to a door trim that enhances the operation of the side impact system.
2. BACKGROUND OF THE INVENTION
The Insurance Institute for Highway Safety (IIHS) side impact proposal poses a big challenge for automobile manufacturers. The Insurance Institute for Highway Safety has tested many vehicles, ranging from small cars to large sports utility vehicles. Generally, none of these vehicles received exceptional ratings.
The problem recognized with the testing by the Insurance Institute for Highway Safety (IIHS) is a much heavier IIHS barrier (1500 kg vs 1370 kg for FMVSS214 testing procedures) crashes into vehicles at 50 kilometers per hour (kph) and the sides of vehicles are not strong enough to reduce the speed of the barrier before the vehicle interior impacts the occupants. To attain better safety performance in the IIHS testing procedure, automobile manufacturers need to effectively and cost efficiently reinforce vehicle sides or to change the crash dummy kinematics.
The Insurance Institute for Highway Safety side impact testing is a new proposal. Currently few mechanisms have been developed specifically for these testing procedures. Traditional side impact development concentrates on reinforcement of vehicle B-Pillar, rocker, door beam, floor pan, etc. These reinforcement mechanisms might have provided some benefits on previous side impact testing procedures but will have limited effect on IIHS side impact testing due to the fact that IIHS side impact barrier is much larger, e.g. 200 mm bigger vertically than previously used impact barriers, is positioned much higher, e.g. 100 mm higher from the ground than the position of the previously used impact barrier, and is significantly heavier than the previously used impact barrier. Cost and weight increase are some of the other issues in the reinforcement design.
One perceived problem is that severe intrusion by the impact barrier will overwhelm any small design changes, even for large floor pan reinforcement, which can be very costly in application. The floor pan has to go through the floor tunnel where the curved shape will make the reinforcement weaker. Therefore, some other mechanism will be needed in order to put significant impediment forces on the impact barrier to reduce the speed and dynamic crush of the impact barrier, and at the same time change the crash dummy kinematics, such as, for example, pushing the crash dummy from the pelvis area. Studies show that changing dummy kinematics is more effective than reducing general intrusion from the impact barrier because of the large crash zone for vehicle side impacts.
In an IIHS side impact event, the thorax region of the crash dummy is pushed further inboard than the pelvis area of the crash dummy under conventional vehicle door structure, thereby causing the lower spine of the crash dummy to bend. The upper body of the crash dummy drags the lower body to move inboard. Since the lower body represents a large portion of the crash dummy weight, the thorax and abdomen rib regions are under severe pressure to deform. Most vehicles are rated poorly on the IIHS side impact tests because of excessive rib deflections.
Pelvis pusher blocks are widely used to push the pelvis region of the crash dummy further inboard to release the pressure in the thorax and abdomen areas. The pelvis pusher block is typically made from soft foam, i.e. foams of 25 or 30 psi. One problem with the use of pelvis pusher blocks is that the pelvis pusher block has to push through interior door trim. Since the armrest is close to the pelvis area, the inwardly moving door trim will cause the armrest to move inboard and, therefore, the abdomen ribs of the crash dummy are under severe pressure to deform.
Prior art door structures have been developed to resist side impact forces. In U.S. Pat. No. 5,000,509, issued to Sinnhuber et al. on Mar. 19, 1991, the side impact is absorbed by the door structure through low deformation sections and braces. In U.S. Pat. No. 5,098,124, issued to Breed et al. on Mar. 24, 1992, impact energy absorbing members extend to the bottom of the door to cushion the occupant from side impacts. In U.S. Pat. No. 5,110,176, issued to Curtis on May 5, 1992, side impact forces are absorbed by a cantilever brace attached to the vehicle floor. In U.S. Pat. No. 5,435,618, issued to Sacco et al. on Jul. 25, 1995, a welded structure of plates and transverse members transfers energy to the sills. In U.S. Pat. No. 6,364,398, issued to Kim on Apr. 2, 2002, a pusher is attached to a door reinforcing member to force the door trim and the passenger inwardly upon side impacts.
In addition to side impact absorbing structure, other patents have been granted to door trim features that deploy on side impact to facilitate the absorption of the side impact forces. As an example, U.S. Pat. No. 5,482,344, issued to Walker et al on Jan. 9, 1996 teaches a door trim panel that is releasably attached at the bottom portion thereof to release from the occupant compartment to allow the energy absorbing member to enter into the occupant compartment in a substantially undeformed state. In U.S. Pat. No. 5,603,548, issued to Gandhi et al. on Feb. 18, 1997, internal pushers extending between a target member and the bottom of the inner door trim to push the bottom of the inner door trim into engagement with the seat structure upon encountering a side impact.
It would be desirable to provide a door trim structure that would enhance the use of pelvis pusher blocks to protect the occupants of the vehicle during side impacts.